这里我截取的是一个图片，实际上是会动的。废话不多说，上代码。
HTML：
<canvas></canvas>
CSS：
/*css reset */ body,p,div,ol,ul,li,dl,dt,dd,h1,h2,h3,h4,h5,h6,form,input,iframe,nav { margin: 0; padding: 0; } html,body { width: 100%; height: 100%; } body { font: 14px Microsoft YaHei; -webkit-text-size-adjust:100%; -moz-user-select: none; -webkit-user-select: none; user-select: none; position: relative; background: #000; } #canvas { width: 100%; height: 100%; display: block; opacity: .8; }
JS：
// 音量大小,0.01-1 //宇宙特效 var canvas = document.getElementById('canvas'), ctx = canvas.getContext('2d'), w = canvas.width = window.innerWidth, h = canvas.height = window.innerHeight, hue = 217, stars = [], count = 0, maxStars = 1100; //星星数量,默认1300 var canvas2 = document.createElement('canvas'), ctx2 = canvas2.getContext('2d'); canvas2.width = 100; canvas2.height = 100; var half = canvas2.width / 2, gradient2 = ctx2.createRadialGradient(half, half, 0, half, half, half); gradient2.addColorStop(0.025, '#CCC'); gradient2.addColorStop(0.1, 'hsl(' + hue + ', 61%, 33%)'); gradient2.addColorStop(0.25, 'hsl(' + hue + ', 64%, 6%)'); gradient2.addColorStop(1, 'transparent'); ctx2.fillStyle = gradient2; ctx2.beginPath(); ctx2.arc(half, half, half, 0, Math.PI * 2); ctx2.fill(); // End cache function random(min, max) { if (arguments.length < 2) { max = min; min = 0; } if (min > max) { var hold = max; max = min; min = hold; } return Math.floor(Math.random() * (max - min + 1)) + min; } function maxOrbit(x, y) { var max = Math.max(x, y), diameter = Math.round(Math.sqrt(max * max + max * max)); return diameter / 2; //星星移动范围，值越大范围越小， } var Star = function() { this.orbitRadius = random(maxOrbit(w, h)); this.radius = random(60, this.orbitRadius) / 10; //星星大小,值越大星星越小,默认8 this.orbitX = w / 2; this.orbitY = h / 2; this.timePassed = random(0, maxStars); this.speed = random(this.orbitRadius) / 80000; //星星移动速度,值越大越慢,默认5W this.alpha = random(2, 10) / 10; count++; stars[count] = this; } Star.prototype.draw = function() { var x = Math.sin(this.timePassed) * this.orbitRadius + this.orbitX, y = Math.cos(this.timePassed) * this.orbitRadius + this.orbitY, twinkle = random(10); if (twinkle === 1 && this.alpha > 0) { this.alpha -= 0.05; } else if (twinkle === 2 && this.alpha < 1) { this.alpha += 0.05; } ctx.globalAlpha = this.alpha; ctx.drawImage(canvas2, x - this.radius / 2, y - this.radius / 2, this.radius, this.radius); this.timePassed += this.speed; } for (var i = 0; i < maxStars; i++) { new Star(); } function animation() { ctx.globalCompositeOperation = 'source-over'; ctx.globalAlpha = 0.5; //尾巴 ctx.fillStyle = 'hsla(' + hue + ', 64%, 6%, 2)'; ctx.fillRect(0, 0, w, h) ctx.globalCompositeOperation = 'lighter'; for (var i = 1, l = stars.length; i < l; i++) { stars[i].draw(); }; window.requestAnimationFrame(animation); } animation();